Contact metallization with new contact plug materials (i.e., other than tungsten) is desirable for chip design and manufacturing. Minimizing contact resistance is further desirable for this application, and an adequate diffusion barrier atop of alternative contact materials may improve or enable these applications. In addition, diffusion barrier material possessing catalyst properties for electroless plug deposition is desired.
Ultrathin conformal barrier layer formation by electroless deposition is desirable due to the selective and conformal nature of electroless deposition processes. Since the surface of some contact materials are not catalytic toward direct electroless barrier deposition, techniques are needed for performing electroless deposition on these materials.
Palladium (Pd) is used for activation in electroless deposition processes. However, Pd is undesirable for use with contact metallization due to its diffusion into copper and silicon dioxide (SiO2).
Thus, what are needed are techniques for improving integration of various contact materials in semiconductor devices.